1. Field of the Invention
The present invention relates to an information processor using an optical storage medium, and more particularly to an information processor for processing data at a faster rate when an optical storage medium such as an optical disk is used as a storage medium as opposed to other types of storage for image processing system such as a video game machine or a home computer.
An image processing system with a plurality of central processing units (CPUs) is disclosed for example in Japanese Patent laid open Publications 56-66735/1981, 56-124964, 58-106650/1983. These systems have the same kind of CPUs as to the processing rate and the bit number, i.e., the number of bits in data operands processed by the CPU. The CPUs or processors are connected in parallel to a main common storage device such as a semiconductor memory, so that any CPU or processor among them can access the main storage device, and the program to be processed can be distributed among the CPUs.
However, in the above-mentioned prior arts, if the storage device is an optical storage medium as a CD-ROM or an optical disk, the CPUs cannot access the optical storage medium directly with using time sharing. Further, such a system using the same kind of CPUs cannot be applied because the data are stored in a bit serial format and/or they are stored after data compression. For example, the data read optically from an optical storage medium must be converted to a data format used by the CPUs, and if the data is compressed, it must be expanded. These delays plus complex operations with respect to the data result in a long processing time and user wait. On the other hand, if a plurality of CPUs of fast processing time is used, the cost of the system becomes high. Further, if the system is constructed using an information processing unit already sold, it is impossible to change all CPUs to CPUs of faster processing time.